a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)=-3
a(1/b+1/c)+b(1/a+1/c)+c(1/a+1/b)+a*1/a+b*1/b+c*1/c=0
a(1/a+1/b+1/c)+b(1/b+1/a+1/c)+c(1/c+1/a+1/b)=0
(a+b+c)(1/a+1/b+1/c)=0
将1置换成a^2+b^2+c^2得:
(a+b+c)*(a+b+c+2(a^2+b^2+c^2))=0
(a+b+c)*(a+b+c+2)=0
将a+b+c看做一个整体
a+b+c=0或-2